为解决反射式拼接 CCD相机成像渐晕问题, 依据辐射定标理论采用多亮度点渐晕图像校正算法处理渐晕图像。首先, 针对典型的反射镜拼接方式, 分析了成像时产生渐晕的原因; 然后, 根据实验室多亮度等级下成像结果, 得出拼接 CCD渐晕区各像元数码输出值与入瞳处辐射亮度成线性关系的结论; 最后, 应用多亮度点校正算法, 计算出渐晕区各像元的渐晕校正因子, 校正渐晕图像。实验结果表明: 对非均匀性大于 10%的多幅原始渐晕拼接图像, 校正后, 图像的非均匀性下降到 0.5%以内, 可满足反射镜拼接 CCD相机非均匀性指标要求。

To solve the problem of the vignetting resolution in mosaic CCD camera imaging based on reflector, the multi-radiance vignetting correction algorithm is studied. Firstly, the main reasons of the typically Reflector-based mosaics camera’s vignetting phenomenon were analyzed. Then, analyzing the vignetting images under multi-radiance levels in radiometric calibration experiment, each pixel’s DN (Digital Number) in vignetting imaging region is increasing with the rise of the incident radiance, nearly linear relationship. Finally, the each pixel’s correction factors in vignetting imaging region were calculated using the multi-radiance vignetting correction algorithm, and the correction factors were used to correct vignetting image. In correcting experiments, the original vignetting images’ non-uniformity is above 10%, and corrected images’ non-uniformity is reduced to below 0.5%. Correcting results meet the requirments of non-uniformity of the reflector-baesd mosaics camera.